It’s a curious one. Of the entire set:
Toy Knife (dagger) has 145fp
Precisely Calibrated Stringstick (bow) has 0fp
Barely Attuned Magic Thingy (staff) has 310fp
Lethargic Sentience (wand) has 145fp
Unstable Anomaly (sword) has 0fp
(no katana, even though the items were released in summer 2014 & ninja was in the game then)

Only reason I can think of is it could be tied to the rarity of how we originally obtained the items via Steam trading cards: if sword/bow were the most common, wand/dagger less common, and staff the rarest, the fp could’ve been tuned to match this.

Probably should be ironed out in current Rotmg, now that they are all presumably drops of equal chance in Mad God Mayhem.